[InfluxDB, Grafana] Hostnames update ends with discontinuity and missing data


Using influxDB1.8, icinga and grafana.

1- I made modifications on the names of the monitored hosts (via icinga)
2- I changed the Retention policy [3 Months] as default RP -> I found that the shard group duration is automatically modified to 24h --> then I changed it again to 7days

–> in Grafana I used both retention policies in the queries
–> as the Hostnames are used as variable in Grafana, I could see a complete continuity of graphs in time once I choose the new name: it means even with the modified new names, I could see old performance Data which was attributed to the old Names)

After ~ 1 day, everything is unfortunately changed -> I can’t see any old performance Data anymore. Only when I manually use the old hostnames in the query (with previous RP)

Can anyone please explain to me what happend? Why I failed to maintain the continuety of the graphs after changing hostnames?
Thanks in advance!

What you described is the expected behavior to me, as you have probably changed a tag value,(hostname or something similar).
Once the new name took effect (I have no idea about how Icinga works), all the data will use the new name, effectively creating a new set of data, with a different hostname.
if you use “hostname” as a filter in Grafana (which is probably the case), then will find old and new name, one with data up to moment X (old), and the other one with data form X onward (new)

Sadly for you, there is no workaround for this one, as you can’t update tag values in InfluxDB, if you really want to see also the old data, you must export, edit and insert them back in InflxuDB

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